Taper-thread gauge



May 22, 1928. 1,671,032

. i c. G. JOHNSON v TAPER THREAD GAUGE Filed Aug. 23, 1926 I INVENTOR.

i ii; /5 BYW ATTORNEY kinds are in common use for gauging Patented May 22, 1928.

UNITED, STATES PATENT OFFICE.

CHARLES GUSTAI' JOHNSON, F HARTFORD, CONNECTICUT.

{PAPER-THREAD GAUGE.

Application filed August 28, 1928. Serial No. 180,975.

This invention relates to an improved apparatus for gauging taper threads, Gauges and gauging apparatus of various 1s inefficient and objectionable for various reasons, among which may be mentioned the considerable amount of time required in the gauging operation and the depending entirely upon observation for the gauging accuracy. It is the primary object of my inventionto provide an improved apparatus for gauging taper threads which will overcome these objections.

Inv auging straight threads, contact with the t reads themselves need only'be considered, and as above stated, various kinds 1 of gauging apparatus is in common use for this purpose, these apparatus being very quick acting and not depending upon observation for their accurac In gauging taper threa s, however, another factor is associated with the thread and must be considered. This factor is the diameter of the threaded piece as measured from the end thereof. This end can giiuging elements are located on the gauge ame at opposite sides of this guide surface and' diverge outwardly. therefrom in such a manner that the grooved opposlng faces thereof cooperate to form a taper 66 gauged.

thread gauge. It is' another object of my invention to provide an improved taper thread gauge embodyin uch a guide surface for the end of the threaded piece to be In gau ing straight threads, the work piece can e moved axially to accommodate the relative position of the gauging elements. However, in gauging taper threads, as above outlined, the axial work piece is fixed and, wlth the gauging elements fixed against movement axlally of the work piece, it would be necessary to rotate the work piece sufliciently to bring the threads thereof into alignment with the thread grooves in the gauging elements and such operation would require a considerable amount of time. In my improved gauge, I avoid this requirement by permitting the gauging elements to have a slight move- 70 ment axially of the work piece, resilient means normall tralized, Furthermore, while I preferably use gauging elements of the annular grooved roll type, such as shown in my copending 7 application, Serial No. 404,791,.filed August 20, 1920, and renewed October 6, 1925, it will be understood that my invention herein is of broader scope and anticipates the use of any type of gauging element desired. It is a further object of my invention to provide an improved taper thread gauge embodying these novel features.

In the accomparkying drawing, I have illustrated one speci c embodiment of my invention, the claims appended hereto being relied upon for that purpose.

Referring to the figures of the drawing:

Fig. 1 is a side elevation of a thread gauge embodying my invention.

Fig. 2 is an end view thereof.

Fig. 3 is a longitudinal sectional view through one of the gauging elements.

The accompanying drawing illustrates I my invention in the form of a snap gauge,

the frame of which is indicated by the reference character 1, This frame is similar to that shown in my above-mentioned application except that a solid web 2 is provided between the gauge ends 3. The guide surface above mentioned is provided on this web preferably in the form of a separate hardened steel plate 4 having. a plane ground guiding'face 5 for receiving the end of the work piece. The plate may be held in place by screws 6. The two pairs of gauging no position of the 60 holding the elements censealed in such position elements or anvils 7 and 8 illustrated in the drawing are preferably of the annularly grooved roll type shown in my said 'eopending application. Each of these elements comprising a roll annularly grooved to provide aplurality of thread engaging annuli 9 having the crests screw thread to be tested. Each roll is rotatably mounted on a supporting post 10 having an eccentric portion ll mounted in the.gauge frame. The post is held in the frame by a screw 12 having a nut 13 thereon within a bore 14 in the end of the post. The elements can be adjusted transversely by loosening the nuts 13 and rotating the posts, as will be understood. The ostscan be by filllng the bore with wax.

The two supporting posts 10 of each pair of gauging elements 7 and 8 are located opposite each other on opposite sides ofthe guide plate 4 and project outwardly of the gauge framein relatively diverging directions in such a manner that the grooved opposing faces thereof cooperate to form a taper thread gauge. The annuli 9 are-preferable spaced to double the thread pitch thread plus twice directl become cramped.

whereby the same engages every other thread of the work piece.

As have been stated above, it is desirable to permit the gauging elements to have a slight movement axially of the work piece. As illustrated, I mount each gauging roll for free sliding and rotary movement on its supporting post-and normally hold each roll in its centralized position by a pair of springs 15 respectively engaging against the ends of the roll. The amount of play per mitted each roll ma be such as is foun from experience to be the most desirable, this amount necessarily being slightly more than one-half the screw thread pitch in each direction, so that the thread may be placed in the gauge at any point of its circumference without causing the gauging rolls to- I preferably permit each to the pitch of the screw the diameter of the wire used in the springs 15, plus an additional amount of about .015 inch.

The gauge illustrated in the drawing is a snap gauge in which the gauging elements roll a play equal 7 are the go pair and the gauging elements 8 are in the no go pair. The gauging elements are ad'usted to accurate working position as follows: The threaded end of a master lug gauge 16 is placed flat against the gui e between the pair of gaugmg elements These elements are then'ad usted to contact therewith. The gaugingelements 8 are set 1n like manner except-that a thickness gauge or plate" is placed between the plug gauge end and-the surface 5 which will hold the end of the plug gauge a spaced thereof formed to fit the face 5, as illustrated in Fig. 2, and

The slight axial play permitted the gauging rolls allows the same to move sufficiently to engage the work threads. As in other snap gauges, the work is acceptable if it passes between the g0 elements 7 but will not pass between the.no go elements 8. The elimination of the necessity of gauging taper threads by observation and the time saved by the use of my invention, as well as the other novel attending features thereof, are all believed to be obvious from the disclosures herein.

Having thus described my invention, what I claim and desire to secure byLetters Pat ent is? 1. A taper thread snap gauge comprising the combination of a frame, meansproviding a work guiding surface thereon, and a pair of grooved thread gauging anvils mounted on the frame respectively on-opposite sides of the work guiding surface and projecting outwardly from the frame in relatively diverging directions in such manner that-the rooved opposing faces thereof coo erate wit ,the work guiding surface and eac 1 other to form a trigona contact for gauging a taper threaded piece, the arrange ment being such that when the threaded end of the threaded piece is in contact with the work guiding surface the grooved faces of the two anvils engage the threads on opposite sides of the piece.

2. A taper thread snap gauge comprising the combination "of a frame, two pairs 0 annularly grooved threadauging rolls mounted thereon in spaced re ation, the two rolls of each pair being located opposite each other and-projecting outwardly of the frame in relatively V such a manner that the grooved opposing diverging directions in faces-thereof oo-operate to form a taper thread gauge, one pair of rollsbeing the go pair and the other pair being closer together and constituting the no go air, and means for adjusting certainof t e 'rolls transversely.-

3. taper-threadsnap gauge comprising.

outwardly of the frame directions in such a modate the "manner that the grooved opposing faces I and the other pair bein closer together and constituting the no go pair, means for adjusting certain of the rolls transversely, and resilient means normally holding the rolls against axial movement but permitting a slight axial movement thereof to accomposition of the thread tobe gauged.

a .4. A taper thread snap gauge comprising the combination of a frame, means providing a work guiding surface thereon, and two pairs i of grooved thread gauging anvils mounted on the frame in spaced relation, the two anvils of each pair being located opposite each other on opposite sides of the work guiding surface and projecting outwardly in relatively diverging directions in such a.

manner that. the grooved opposing faces thereof co-operate to form a taper thread gauge, one pair of anvils being the go pair and the other pair being constituting the no go pair.

'5. A taper thread snap gauge comprising the combination of a frame, means providing a workguiding surface thereon, two

palrs of annularly grooved thread-gauging rolls mounted on the frame in spaced relation, thetwo rolls of each pair being 1o closer together and projecting outwardly in relatively diverging directions in such a manner that the-grooved opposing I faces thereof co-operate to form a, taper thread gauge, one pair of rolls being the go pair and the other pair being closer together and constituting the no go pair, and means for adjusting certain of the rolls transversely.

6. A taper thread snap gauge comprising the combination of a frame, means providing awork guiding surface thereon, two pairs of: annularly rooved thread-gauging rolls mounted on t e frame in aced relation, the two rolls of each pair being located 0 posite each other on opposite sides of t e work guiding surface and projecting outwardly in relatively diverging directions in such a manner that the grooved opposing CHARLES eusru JOHNSON.

cated opposite each other on op osite sides of the work guiding surface and faces thereof co-operate to form a taper 

